strlen function

C

Function

Reference manual

@see man strlen

The strlen function calculates the length of a null-terminated string by counting the number of characters in the string (excluding the null terminator). It returns the length of the string.

Syntax

size_t strlen(const char *str);

Parameters

• str: The input string for which the length is to be determined.

Return value

Returns the length of the string, which is the number of characters in the string.

Example

In the following example we use the strlen function to count the number of characters in the string “Hello, World!” and we output it.

#include <stdio.h>
#include <string.h>

int main(void)
{
    const char str[] = "Hello, World!";
    size_t length = strlen(str);

    printf("String length: %zu\n", length);
    return (0);
}